N-alkyl-n-(sulfophenylthio) alkylaminoanilines



Patented July 15, 1952 N-ALKYL-N- sULFoPHENYL'rH'Io) ALKYLAMINOANILINES William Howells Vinton, Parlin, N. J assignor to v E. I. du Pont de Nemours and Company, Wilmington, Del., a corporation of Delaware No Drawings Application May '5, 1951,

Serial N0. 224,823

. 1 This invention pertains to v a new class of N-substituted aminoaniline derivatives. More particularly it pertains to N-alkyl-N -(sulfophenylthioalkyl) aminoanilines. These compounds are useful as photographic developing agents.

Variousi arylenediamines have; been used as photographic developing agents, but themost im-. portant of them, namely} para-phenylenediamine and its 1ower-N,-N'-dialkyl derivatives have the disadvantage that they are readily absorbed by the skin and give rise to dermatitis. Since these agents are strong photographic developers and readily couple with color formersduring the development of latent silver halide images to produce quinoneimine or azomethine dyeimages in situ with the silver images, they are used in most commercial processes ofcolor photography. The compounds, however,1due1to their toxicity constitute a-health' hazard in photographic developing laboratories.

An object of this invention is to provide a new class of photographic'developing agents. A further object is to provide a new class of photographic developing agents which are useful in chromogenic development and are free from toxic effects, The more specific object is to provide a new class of N-alkyl -N -1(sulfophenylthioal kyl)aminoanilines. Still other objects will;be apparent from the following description of the invention. a 7 I The new compounds of this invention may be represented bythe following general formula:

where R is a hydrogen atom or an alkyl or substituted alkyl group oran alkoxy or substituted alkoxy group; n isa-positive integer from 2 to 10, m is 1 or,2 and alkyl contains from 1 to 6 carbon atoms. Among the useful alkyljradicals for R there .".may ,be mentioned CH3, .-C2H5, -.CH(CH3) 2'and amongthe useful substituted alkyl' radicals R there may. be mentioned CH2OH and 'CHzCl. Suitable specific alkoxy radicals for R include OCl-l3, -OC2H5 and OCH(CH3)2. R, however, preferably is hydrogen or an unsubstituted alkyl or alkoxy radical of 1 to 3 carbon atoms.

It is important that the tertiary nitrogen atom and the sulfophenyl group in the above compounds be separated by at least two methylene (CH2) groups in order to obtain a high degree lines are used in place of the N-alkyl aniline in 3 Claims. (01. 260-510) of photographic development. The'compounds where n is 3 to 6 and alkyl contains 1 to 4 carbon atoms are preferred. When n is greater than 10 thecompounds still possess some developing properties but are less satisfactory than compounds covered by Formula I because the developer has a slow rate of diffusion into a colloid silver halide-emulsion layer and it is more difficult to wash such compounds out of the colloid silver halide emulsion layers. Y The compoundsofFormula I may be prepared by the following series of chemical reactions: (at) preparation of an N-alkyl-N-(phenylthioalkyl) aniline byreaction of an omega-halogen substituted alkyl phenylthioether containing the halogen and thioether groups on the opposite ends of;the straight chainalkylene radical with an N-alkylaniline, e. g., N-mthylanilinali-ethylaniline or N-butylaniline. v This reaction is usually carried out under neutral to'alkaline conditions; (b) preparation of N-alkyleN-( om ega-sulfophenylthioalkyl) anilines by the reaction of the tertiary amine derivative obtained in step (a) with a sulfonating agent, e. g., hot concentrated sulfuric acid; (c) preparation of the. corresponding p-nitroso-N-alkyl N (omega-sulfophenylthioalkyl) aniline by reaction of the compound obtained in step (b)' with nitrous acid; vand (:1) reduction of the nitroso compound obtained'in step" (c), e.. g., with iron or catalytically with hydrogen to the corresponding amine'having the general Formula I. v When Iii-methyl-m-toluidine, N-ethyl-m-toluidine, N-methyl-m-anisidine, N-ethyl-m-anisidine, or similarly nuclear substituted N alkyl anithe' above syntheses one obtainsthe correspondingly substituted developers. f Thisinvention will be further illustrated by the following examples. They exemplify suitable specific methods for the preparation of the compounds and illustrate their uses and properties but are not intended to limit the invention.

EXAMPLE I N-ETHYL-N- (GAMMA-DISULFOPHENYLTHIOPROPYL) P-PHENYLENEDIAMINE HYDROCHLORIDE A. Gamma-chloroprop yl phcnyl thioether of thiophenol and 3'75 m1. of water. The mixture was refluxed for 3 /2 hours (whereby the NaOH was consumed) cooled to room temperature, saturated with sodium chloride, and extracted twice with diethyl ether. The solution was dried over anhydrous sodium sulfate, the diethyl ether distilled at; atmospheric pressureyand the v.;residual oil was distilled ina precision still of about 1'5 theoretical plates to give, 169.3 grams (91% of theory) of gamma-chloropropyl'phenyl thioether i 6 boiling at 124-125/7 mm. (11 1.5714

B. N-ethyl-N-gamma-phenylthiopropyldn'ilme- V to about 30 0. solid CO2.

A mixture of 168 grams (enamel-mt the compound prepared above and 242 grams 62.00 mols') of redistilled N-ethylaniline waswtirred on }a steam bath under nitrogen for 44 hours; 36=-grams EXAMLPLE II --N-] 1;I,HYLr-N- (.EPsILON-P-S FOPHENYLTHIOAMYL) -1 PHENYZLENEDIAMINE 1A. -chlo1oamyl acetate fi-fih loroamyl acetate (B. P. 107-110/25 mm.,

n-5 134373) "was prepared by the method described by Cason et al. (J. Org. Chem., 14, 41

of sodium'hydroxide in 200 ml. of water was stirred with the cooled reaction mixture and the top organic layer was separated, dried over 'potassium hydroxide, anddistilled under nitrogen from aiprecision .still to give 99.0 grams of a product "boiling at 1191192 C. at3- millimeters ra -5 s; 15072 Q. ."N-eth'cul-N- (gamma;disuljophenylthiopropyll aniline I f lf l-i netywig h-t grams of the 'diamine -prepared above" was 'sul fonate'd inthe mannerdescribed under II-E'. The reaction product was; obtained as a thick oil which not crystallize.-

DlNitrosat-ion of N--ethyl -'N (gamma-disulfophenyl-tlwop'ropyl) aniline I The N ethy1'-N-(gamma-disulfophenylthiopropyDaniline' obtaineddn-step 0 1-40 grams, 0.? incl) was nitrosated by the method given A. Blatt; Organic Syntheses Collective v01- UmeII, page" 223; John -Wiley 8i Sons..- New" York 1-943. The; nitroso compound separateda's afdark red-tar which wasfinally crystallizedto a red 'solid' wei-ghing113 grams (ti-810% of' theory) E. Reduction of .p-nitro'so N ethyFN-(gamma- "disulfopherflylthiopropyll '-aniZi1L-e Forty grams o1v iron powderwas' added in small portions to a..solution.of. 60.'5 grams fof theabove prepared disulfonic acid in 168. milliliters Oi IGOR centr'at'ed hydrochloric acid and 500tm12 o'f: water. 'I'he'temperature 1 was kept below 35 C'f'with". ex ternalicogoling. After the 'nitrosoj color had been destroyed; the temperature was raisedioifill C. for 15 minutes and theunreacted'ironwas'filtered with suction, the solution was. cooled and made strongly. alkaline by; adding a1. 10% sodiumihy-j droxideiisolution. I The iheavy elatinous-prec'ipi times -with 50 m1. portionsofmethanol; The

8.7 grams of methanolinsoluble residue still gave af'a-int-color developer test. The" methanol was concentrated under-reduced pressure -inarnit'rog'enatmosphere from a hot "water bath to about 150-1211. The 4.49" grams 'of grey solid which-had separated was filtered with-suction, wa;shed with cold: methanol and with ether. The filterate'wa's B. Pentamethylene chlorobromide Pentamethylene chldrobromide B. P. (94-99 (1/26 'mm, n .4862')--was prepared-by-nacting chloroamyllacetate with hydrobromici acid by the method'de'scribed by Cason et; a1. '(loc.-'cit.--).

.C. Epsilon-chloroamylmhenyl .thioeth'ei A solution of 552 grams of sodium hydroxide in 5175 ml; of water was: added with stirrin'g' ov'er a 45m inute period: to a refluxingmixture of 256 grams ofpentamethylene chlorobromide 152 grams of .t'hiop'henoland" 325 ml; of water. The mixture was refiuxed'iand 'stirre'd for' 3 hou-rs and left standing overnight at room temperature. The upper organic layer was-separated, dried-over c'aClzandj hactionated through a 12 mm. x 50' cm; wire gauze screen' column: at a reflux ratio greater than 10:1 and usinga nitrogen-bleed. The yield of ep'silonwhloroamy'l phenyl 'thio'-' ether d'istill'ingiat 'l'l i l'lfi at 2:5 mm. "(W5 1.55190)' was "72 percent of theory based on the thiophenol used.

D; N -ethyleN-epsilon-phenylthio-amylaniltne -A mixture of z-ls-grams (0.99 mol) ofepsilonchloroamyl 'phenyl'thioether and '254'grams (212 mol's) "of N ethylaniline wa -stirred under-nitrogen for 50-hours at 1 55* 65- C; The reaction E. N-ethyZ-N- (epsilon-sulfopheng lthio-amyl) ani- '.line"' 'Sixtyigrams {0.1200 moDj off.am ine' jprepa'1ied above was sulfonatedbyjadding? it dropwisew'ith stirring'to 8.5 m1. of. concentrated sulfuric acid'at' -110" C. over" a. 20m'inute period and ,then stirrin at'1'00i-'110 0.."fidr an additional? .10. min utes until the solution was completely soluble in 5%fispdium hydroxide solution. 'The reaction product'separatedas a white 'tafiy-lijke'material. which .crystallized'upon long working with '10; changesof ice water; weight '8'1.2' grams',11('83.5 percent of theory), M. P. 123-125 C. It-was insoluble in water, acetonitrile, pyridine, nitroethane, dioxane, ethyl acetate;tetrahydrofurfuryl alcohol, and in methanol. 'Itwas soluble in concentrated'sulfuric acid and in dilute sodiumhydroxide.

'cator effect (turning more blue).-

F. Diazomoupling, of N'-ethybNesulimphenylthio amylaniline withp-toluidine' A'diazonium: chloride solution, prepared from 8.2 grams (0.076 mol) of -p-toluidine, was added with stirring to a solution of 36 grams (0.076 mol), of the amine in '200 ml. of water containing grams of sodium hydroxide. The temperature of both solutions was below 10 C. The mixture becamedark magenta immediately but no solid separated. Aiterthe-mixture had stoodfor about .15 minutes, grams of sodium hydroxide. dissolvedin 50ml. of waterwas added and the'mixture was allowed tostandin ice for an hour longer. Some dye separated'as a visc'ous,..red, oily paste. I"his did not become crystalline iupon standing overnight inthe ice chest, so .the mixture was diluted'withfanequal volume of'water, heated to 50'and reduced with sodium-hydrosulfite until a test portion noloriger showed the presence of an azoxdye. i The yellow solutionwas filtered to remove p'toluidi'ne which had. separated and then acidified with acetic acid.l The gummy solid which separated was dissolved in dilute sodium hydroxide, the undissolved sulfur was filtered, and the solid was reprecipitated with acetic acid as a light brown powder. The process was repeated again and the solid was dried in a vacuum desiccator; weight 12.10 grams, M. P. 237 C. I

The compound is soluble to the extent of about 8.5 grams per liter, of water containing a stoichiometric amount ofsodium hydroxide. ,It is possible to prepare a developer solutioncontaining an adequate amount of the color developer by using potassium carbonate or sodiumcarbonate or other alkalies by the {aid of ,a-hydrotropic wetting agent, e. g., sodium dodecyl suliate. At pH below 3.0, its cyan dyeshoweda sharp indi- Anal. calcd. for C19H26N2O3S2.H2OZ N, 6.79; S, 15.56. Found: N, 6.16; 6.02; S, 15.77, 16.05.

By substituting equivalent amounts of ethylenechlorobromide or other polymethylene chlorobromides, e. g., tetramethylene chlorobromide, hexamethylene chlorobromide, heptamethylene chlorobromide, monomethylene chlorobromide and decamethylene chlorobromide for the trimethylene chlorobromide of Example I or the pentamethylene chlorobromide of Example II till other homologous compounds which fall under eneric Formula I above can be prepared.

Similarly by substituting for the N-ethylaniline 01' Examples I and II or in similar reactions using the chlorobromides in the preceding paragraph the other N-alkylanilines listed before the above working examples one can make still other homologous compounds which come under structural Formula I.

Among the suitable compounds which can be made as just taught are:

N-methyl-N-(y sulfophenylthiopropyl) p phenylenediamine N-methyl-N-(w disuliophenylthiopropyl) p phenylenediamine N-ethyl-N ('y sulfophenylthiopropyl) p phenylenediamine I N-ethyl-N ('y disulfophenylthiopropyl) p phenylenediamine N-propyl-N ('y sulfophenylthiopropyl) p phenylenediamine N-propyl-N ('y disulfophenylthiopropyl p phenylenediamine N-isopropyl N ('y sulfophenylthiopropyl) -pphenylenediamine N-'isopropyl-N+('y disulfophenylthiopropyl) ..pphenylenediamine j t v 4- -N' butyl 4 N -'-1('y sulionphenylthiopropyl)- p phenylenediamine N-butyl N "(*y disulfophenylthiopropyl) p phenylenediamine 1. i-' Q and the co'rrespondingcompounds whichhave in place of methyl, ethyl, propyl, isopropyl and butyl an alkyl-substituted butyl, amyl or hexyl radical. v The photographicdevelopihg properties of the compounds of thispinvention are exemplified by the .compound of Example I (identifiedas A) in comparison with p- -aminodiethylariiline- (identifie d as B) and are shown 'inthefollowing table:

A L .1. Mortoldyer co atihg 7 Block Speed Gamma Base+Fog te to ma e-: r-

In the foregoing table the cyan, magenta and yellow coatings were dispersions of light-sensitive silver iodobromides in polyvinyl acetal color formers of aromatic halides of the type described in U. S. Patents 2,397,864, and 2,380,033 and U. S. applications Ser. Nos. 9,330, filed February 19, 1948, now U. S. Patent 2,513,190 and 29,921, filed May 28, 1948, now U. S. Patent 2,538,257. In the table gamma refers to the development factor and fog relates to the density of development in the unexposed portion of the photographic film. Block speed is an arbitrary figure indicating the speed of the developer. If a developer has a block speed one unit less than another, this means that the photographic film will require about twice the degree of exposure to give an image of the same density as the second under the same conditions of development. Gamma is defined in Neblette, Photography page 412 (published by D. Van Nostrand Company, 1942). Values of the block speed and/or gamma comparable or superior to those of the commercial developer, p-aminodiethyl-aniline, are important. Increases are shown in the table for certain of these values. Particularly important is the fact that the new developers cause less fog than the p-aminodiethylaniline.

The compounds when employed as photographic developing agents may be used as the free acid or as a suitable derivative of the sulamass? -fonic Zaci'd 'groupfei'g :the'ialkali-'imetalzw ammonium salt, according to the't'solubiiityreqmrements of -the system. The --developing, agents 7 may be used in developer formulationsrcontaining color formersfor color development of exposed silver halide containedtin'gelatin"tortsynthetic water-permeable colloid binding agents for silver halide grains. lhey may 'be (used in the-color development of pHOtOgrapIiicYfil-msmntaining immobile color formers in 'theIlightsensitive silver halide emulsion layers, particularly films. ofi-the typedescribed in" U. 'S.' Patent No. 2397364,; I

' V I-he ,nov'eldeveloping agents of-this invention can be admixed Withfotlier conventional constituents of photographic developers including alkaline materials; e. g.,sodium carbonate, potassium carbonate sodium hydroxide, lithium hydroxide; preservatives, e. g., lithium, sodium, potassium, and ammonium sulfites and bisulfites, amine salts of sulfurous acids, for example, trietha nolamine sulfite, morpholine sulfite, tetramethylammonium .sulfite, trimethylbenzylammonium sulfite; restrainers, e. g., sodium, potassium, and lithium chlorides, bromides and iodides, ammonium bromide; other ingredients, e. g., emulsion-hardeners, --for -exampl e,- potassium aluminum sulfate, chrome alum; bufiieiing-salts; e; -g., disodium hydrogen phosphate; sddium' metaborate, borax. The solutions or compositions may be made in two parts, if desired, which are mixed at the time of use.

Thecompoundsof-Formula I where n -isii to are more insoluble than when n'is 12,3013'4 and inorder -to get a sufiicient amount insomtion it may be necessary to-usea smail' amount, e. g., 0.05 to 2.0% by weightof the solutionof a hydrotropic wetting agent. Among the useful agents of this type are saponin, alkali metal salts ofmono diand tri-alkyl naphthalene sulfonic acids, sodium methylene bis naphthalene sulionic acids; alkali metal alkyl sulfates-and alka'li metal a1ky1su1ronatesor"s' 't'o 18 carbon atoms, "etc. Still other'h'y'drotropio agents are described Ullman- ,Encyclopaedie der Technischen Chem'ieflzndf edi, vfol, IX, page 808.

Another advantage of this'iiivention resides in the'fact that the compounds are much less-toxic or'a'llergenic in contact with human skin than paininodiethylani'line. This is of "commercial importance because one of the principle disadvantages of'color developers is their irritating efiect on thelskin. v

The compounds of Formula I, however, are not limited in their 'use as photographic developing agents. Tothecontrary, they are useful chemical "intermediates and'may serve as a basis for the preparation 'ofivaridus other chemical compounds, ertg amides, etc., which may find use as dyes or dye intermediates; 7 As manywi'del'y differentv embo'dimentsoi this invention can be madel-iwithout departing-- from the spirit and: scope thereof, itisto be understood'that'the'invention'is not' to' be limited except-as definedby theiclaims.

What is claimed-is: 1

' 1*. The chemicalRcompounds': of the general formular" a Where 1R is a member taken'from the group-consisting of hydrogenyalkyl'radicalsof l -to '3 carbon'a'toms and alkoxy radicals' ofl to '3 carbon atoms, alk'yl contains l to fic'arbon atoms, n is a cardinal number from {2 to ll) inclusive and m is an-i-nteger from'l "to 2'.

2. 'p-Amino -N-ethyl-N-(gamma -"disulfophenylthiopropyb -an-iline. r

3. p AminoaN- thypiv- (epsilon-p-sulfophenylthioamyl) -aniline. V i

I "WILLIAM'HOWELLS VINTON.

Norre'ferences cit-ed. 

1. THE CHEMICAL COMPOUNDS OF THE GENERAL FORMULA 